Avalanche Forecast

Archived

Feb 10th, 2019–Feb 11th, 2019

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

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We have unusual wind slab conditions in the West-North zone. These winds slabs may be difficult to see Monday due to more new snow. This is a good time to be cautious and avoid open slopes greater than 35 degrees especially at higher elevations and near wind exposed features such as ridgelines and passes.

Discussion

Snow and Avalanche Discussion

We received a report of a large, remotely triggered wind slab avalanche near Ptarmigan Ridge in the Mt Baker backcountry Sunday. This avalanche was approximately 2 feet deep and failed on a layer of sugary facets. We don’t see remote triggering of wind slabs very often. Events like this should cause us to stand up and take notice. Avalanche Details: 2/10/19: SW aspect, 5200 ft. 45-degree slope.

Photo: Remotely triggered wind slab from Sunday.

The recent and expected storm pattern hasn’t been favoring the West North area. That doesn’t seem to change going into Monday. Each of these storms (Friday-Saturday, and Sunday-Monday) are modest, especially by Mt Baker standards. That may just lead to very slow and incremental loading of the snowpack. When we get into situations like this, it’s tough to say when the snowpack will reach its tipping point. It may not be Monday, but only time will tell.

We want to call attention to the odd weather lately. It has been extremely cold for a long time. The snow is falling at very high snow-to-water ratios. This isn’t our normal Northwest pattern. In short: unusual weather often leads to unusual avalanches. Don’t get lulled to sleep an fall into normal travel habits. Keep your head on a swivel and watch the snow around you. If you see anything strange or surprising, that may be the snowpack telling you it’s ready to break.

Snowpack Discussion

New Regional Synopsis Coming Soon

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

Loose Dry

Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.